Honestly, with the wind and how engrossed he is in the view, it takes a moment for Roxas to even register that he'd heard anything at all. Finally it clicks, though, and he turns his head to find the source of the sound. For a moment his expression is warm, pleased to see the other teen, but then he clearly realizes this isn't Takeshi and his mood goes from happy to cautious in a flash.

Not about to be caught in a vulnerable position, he climbs carefully down from the railing so he has two feet on the ground, such as it is.

"What's the last thing you remember?" he asked shortly, opting out of any sort of greeting. He needed to know where this Riku was from. Obviously he recognized Roxas in some capacity. Now he just needed to know what capacity.